The boundary conditions of mass, momentum, energy, and charge appropriate for fluid formulations of edge plasmas are surveyed. We re-visit the classic problem of 1-dimensional flow, and note that the ''Bohm sheath criterion'' is requirement of connectivity of the interior plasma with the external world, not the result of termination of the plasma by a wall. We show that the nature of the interior plasma solution is intrinsically different for ion sources that inject above and below the electron sound speed. We survey the appropriate conditions to apply, and resultant fluxes, for a magnetic field obliquely incident on a wall, including the presence of drifts and radial transport. We discuss the consequences of toroidal asymmetries in wall properties, as well as experimental tests of such effects. Finally, we discuss boundary-condition modifications in the case of rapidly varying plasma conditions.

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The status of coupling the fluid 3D turbulence code BOUT and the fluid plasma/neutral 2D transport code UEDGE is reported, where both codes simulate the edge region of diverted tokamaks from several cm inside the magnetic separatrix to the far scrape-off layer (SOL), thereby including the magnetic X-point. Because the characteristic time scale of the turbulence is short ({approx} 10{sup -5}-10{sup -4}s) and the profile evolution time scale can be long ({approx} 10{sup -2}-10{sup -1} s owing to recycling), an iterative scheme is used that relaxes the turbulent fluxes passed from BOUT to UEDGE and the profiles from UEDGE to BOUT over many coupling steps. Each code is run on its own characteristic time scale, yielding a statistically averaged steady state. For this initial study, the ion and neutral densities and parallel velocities are evolved, while the temperature profiles are stationary. Here the turbulence code is run in the electrostatic approximation. For this example of self-consistent coupling with strong L-mode-like turbulence, the ion flux to the main-chamber exceeds that to the divertor plates.

This document summarizes the Indirect Drive Cold-Loaded (diffusion-filled) Ignition Target design. These targets include a capsule whose strength is insufficient to withstand the room temperature pressure of the DT fuel. These capsules are diffusion filled with DT gas and then cooled to cryogenic temperature. The target must remain at cryogenic temperature until it is shot. Only features that affect the design of the NIF Cryogenic Target System (NCTS) are presented. The design presented is the current thinking and may evolve further. The NCTS should be designed to accommodate a range of targets and target scales, as described here. The interface location between the target and the NCTS cryostat is at the target base / gripper joint.

The photon collider will require the development of high average-power short-pulse lasers to achieve the required rate of Compton backscattering. The MERCURY laser at LLNL has been under development as part of the Inertial Confinement Fusion program. Its basic parameters are well matched to the photon collider requirements and it is currently being commissioned.

An analytical electron fluid model has been developed to describe the plasma response to a propagating ion beam. The model predicts very good charge neutralization during quasi-steady-state propagation, provided the beam pulse duration is much longer than the electron plasma period. In the opposite limit, the beam pulse excites large-amplitude plasma waves. Figure 1 shows the influence of a solenoidal magnetic field on charge and current neutralization. Analytical studies show that the solenoidal magnetic field begins to influence the radial electron motion when {omega}{sub ce} > {beta}{omega}{sub pe}. Here, {omega}{sub ce} is the electron gyrofrequency, {omega}{sub pe} is the electron plasma frequency, and {beta} = V{sub b}/c is the ion beam velocity. If a solenoidal magnetic field is not applied, plasma waves do not propagate. In contrast, in the presence of a solenoidal magnetic field, whistler waves propagate ahead of the beam and can perturb the plasma ahead of the beam pulse. In the limit {omega}{sub ce} >> {beta}{omega}{sub pe}, the electron current completely neutralizes the ion beam current and the beam self magnetic field greatly diminishes. Application of an external solenoidal magnetic field clearly makes the collective processes of ion beam-plasma interactions rich in physics content. Many results of …

Heavy-ion beams impinging on surfaces near grazing incidence (to simulate the loss of halo ions) generate copious amounts of electrons and gas that can degrade the beam. We measured emission coefficients of {eta}{sub e} {le} 130 and {eta}{sub 0} {approx} 10{sup 4} respectively, with 1 MeV K{sup +} incident on stainless steel. Electron emission scales as {eta}{sub e} {proportional_to} 1/cos({theta}), where {theta} is the ion angle of incidence relative to normal. If we were to roughen a surface by blasting it with glass beads, then ions that were near grazing incidence (90{sup o}) on smooth surface would strike the rims of the micro-craters at angles closer to normal incidence. This should reduce the electron emission: the factor of 10 reduction, Fig. 1(a), implies an average angle of incidence of 62{sup o}. Gas desorption varies more slowly with {theta} (Fig. 1(b)) decreasing a factor of {approx}2, and along with the electron emission is independent of the angle of incidence on a rough surface. In a quadrupole magnet, electrons emitted by lost primary ions are trapped near the wall by the magnetic field, but grazing incidence ions can backscatter and strike the wall a second time at an azimuth where magnetic field …

We investigate our ability to improve regional travel-time prediction and seismic event location using an a priori three-dimensional velocity model of Western Eurasia and North Africa: WENA1.0 [Pasyanos et al., 2004]. Our objective is to improve the accuracy of seismic location estimates and calculate representative location uncertainty estimates. As we focus on the geographic region of Western Eurasia, the Middle East, and North Africa, we develop, test, and validate 3D model-based travel-time prediction models for 30 stations in the study region. Three principal results are presented. First, the 3D WENA1.0 velocity model improves travel-time prediction over the iasp91 model, as measured by variance reduction, for regional Pg, Pn, and P phases recorded at the 30 stations. Second, a distance-dependent uncertainty model is developed and tested for the WENA1.0 model. Third, an end-to-end validation test based on 500 event relocations demonstrates improved location performance over the 1-dimensional iasp91 model.

With the constant push to miniaturize existing technologies, there is an ever-increasing need to characterize smaller and smaller objects. X-rays have proven their usefulness for characterizing the internal structure of objects. However, standard x-ray imaging (i.e. projection radiography) methods are not ideally suited for high-resolution imaging of small objects. Lawrence Livermore National Laboratory is currently developing an x-ray microscope that uses high-efficiency reflective (Woelter Type I) optics for imaging millimeter-scale parts at resolutions of better than one micrometer. The optics use multilayer technology to increase the x-ray grazing angle, improving the efficiency of the optics. The Woelter [1] imaging optic focuses x-rays that exit the sample (object plane) onto a scintillator (image plane). The scintillator converts the x-rays into visible light, which can be detected and imaged with a CCD camera. Our optic has a magnification of twelve. The distance between the sample and scintillator is five meters. Figure 1 shows the schematic of the microscope. The Woelter optic consists of hyperbolic and elliptical reflective surfaces. This combination of reflective surfaces was first described by Woelter [1] in 1952. Although simple in concept, the fabrication of a high-quality imaging Woelter optic has proven to be difficult due to the tight …

Results of recent modeling of tokamak edge plasma with the turbulence code BOUT are presented. In previous studies with BOUT the background profiles of plasma density and temperature were set as flux surface functions. However in the divertor region of a tokamak the temperature is typically lower and density is higher than those at the mid-plane. To account for this in the present study a poloidal variation of background plasma density and temperature is included to provide a more realistic model. For poloidally uniform profiles of the background plasma the calculated turbulence amplitude peaks near outer mid-plane, while in the divertor region the amplitude is small. However, present simulations show that as the background plasma profiles become more poloidally non-uniform the amplitude of density fluctuations, {tilde n}{sub i}, starts peaking in the divertor. It is found that in the divertor region the amplitude of n{sub i} fluctuations grows approximately linearly with the local density of the background plasma, n{sub i0}, while the amplitude of T{sub e} and {phi} fluctuations is positively correlated with the local electron temperature, T{sub e0}. Correlation analysis shows that plasma turbulence is isolated by the x-points.

This document summarizes the Indirect Drive Warm-Loaded Ignition Target design. These targets either use a fill tube or the capsule is strong enough to withstand the room temperature pressure of the DT fuel. Only features that affect the design of the NIF Cryogenic Target System (NCTS) are presented. The design presented is the current thinking and may evolve further. The NCTS should be designed to accommodate a range of targets and target scales, as described here. The interface location between the target and the NCTS cryostat is at the target base / gripper joint, the tamping gas gland/gland joint, and the electrical plug/receptacle joint.

We report on a next-to-leading order QCD calculation of the cross section and the spin asymmetry for isolated large-p{sub T} prompt photon production in collisions of transversely polarized protons. Corresponding measurements may be used at RHIC to determine the transversity parton distributions of the proton.

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We investigate the crustal and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet and form a complex tectonic structure. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provided a unique opportunity for studying the high resolution velocity structure. Zor et al. found an average 46 km thick crust in Anatolian plateau using six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver function alone with many-layered parameterization may result in an apparent depth-velocity tradeoff. In order to improve previous velocity model, we employed the joint inversion method with many layered parameterization of Julia et al. (2000) to the ETSE receiver functions. In this technique, the receiver function and surface-wave observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. We consider azimuthal changes of receiver functions and have stacked them into different groups. We calculated the receiver …

An instability driven by an electron temperature gradient in combination with sheath boundary conditions at a divertor plate is considered. It is shown that there exists a mode localized between the divertor plate and the x point. Further propagation of the mode is terminated by a strong shear near the x point. A ''heuristic'' boundary condition at the control surface situated somewhat below the x point is suggested. The mode manifests a strong dependence on the radial tilt of the divertor plate, thereby providing some degree of control over the plasma transport in the divertor leg. Estimates of the diffusion coefficient show that it may reach the Bohm value.

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Heavy-ion induction linacs have application as drivers for high energy density physics studies and ultimately as drivers for inertial fusion energy. Experiments on the High-Current Experiment (HCX) at LBNL explore heavy-ion beam transport at high fill factors (i.e., the ratio of the maximum transverse extent of the beam to the physical aperture). The fill factor has a large impact on the cost of multi-beam induction accelerators, the 80% fill factor compared with 60% would reduce the cost of an HIF driver by about 1/3. With a coasting low-emittance 1 MeV K{sup +} beam, transport through ten electrostatic quadrupoles was achieved at high beam fill factor (80%) without observed emittance growth and with little beam loss ({le} 1%), even though the initial beam distribution is neither ideal nor in thermal equilibrium, see Figure. While 10 quadrupoles are too few for settling questions of emittance evolution in a long system, they are very relevant for studying the rapid initial evolution of the emittance and beam profile that is expected in the front end of an accelerator. Studies at higher fill factors are planned, so that the failure mode can be established. Good envelope control was achieved, suggesting that, in a longer lattice …

The production of spherical poly({alpha}-methylstyrene) (P{alpha}MS) mandrels utilizes a small amount (<0.1wt%) of high-molecular-weight poly(acrylic acid) (PAA) in the suspending medium, which substantially increases the interfacial tension during curing relative to methods using poly(vinyl alcohol) (PVA). However, fully cured capsules made by this method displayed a significant level of high frequency surface debris that became especially problematic when the mandrels were subsequently overcoated. To solve this problem we examined the use of PAA in conjunction with PVA in order to reduce these surface features, and explored numerous variations of concentration and timing of the PVA addition. The optimum conditions were found to be initial use of PAA for centering and symmetry of the mandrels, followed by removal of the PAA medium, washing of the mandrels with water, and finally transfer to PVA solution for completion of the curing cycle.

The use of short laser pulses to generate very high brightness, ultra short (fs to ps) x-ray pulses is a topic of great interest. In principle, fantosecond-scale pump-probe experiments can be used to temporally resolve structural dynamics of materials on the time scale of atomic motion. The development of sub-ps x-ray pulses will make possible a wide range of materials and plasma physics studies with unprecedented time resolution. The Thomson scattering project at LLNL will provide such a novel x-ray source of high power using short laser pulses and a high brightness, relativistic electron bunch. The system is based on a 5mm-mrad normalized emittance photoinjector, 100 MeV electron RF linac, and a 300 mJ, 35 fs solid-state laser system. The Thomson source will produce ultra fast pulses with x-ray energies (60 kev) capable of probing into high-Z metals.

Visual Sample Plan (VSP) is an easy-to-use visual and graphic software tool being developed by the Pacific Northwest National Laboratory (PNNL) to select the right number and location of environmental samples so that the results of statistical tests performed to provide input to environmental decisions have the required confidence and performance. It is a significant help in implementing the Data Quality Objectives (DQO) planning process that was developed by the U. S. Environmental Protection Agency. Gilbert et al. (2001) documented the quality assurance (QA) procedures that were conducted to assure that Version 0.91 of VSP was operating correctly. Subsequently, Version 0.91 was renamed Version 1.0 and placed on the internet at http://dqo.pnl.gov/vsp . Since that time VSP has been enlarged and improved and is now available as Version 2.0. The current document is an expansion of Gilbert et al (2001) to include the QA procedures and testing that were conducted to assure the validity and accuracy of the new features added to Version 1.0 to obtain Version 2.0.

The need for ultra-sensitive actinide measurements continues to expand in the fields of environmental stewardship, nuclear isotope forensics, radiobioassay and environmental research. We have developed a heavy isotope accelerator mass spectrometry (AMS) system at Lawrence Livermore National Laboratory's Center for Accelerator Mass Spectrometry (CAMS). The system was designed particularly for the measurement of actinide concentrations and isotopic ratios. A fast isotope switching capability has been incorporated in the system, allowing flexibility in isotope selection and for the quasi-continuous normalization to a reference isotope spike. Initially, our utilization of the system has concentrated on the measurement of Pu isotopes. Under current operating conditions, background levels equivalent to <10{sup 6} atoms are observed during routine {sup 239}Pu and {sup 240}Pu measurements. Measurements of samples containing 10{sup 13} {sup 238}U atoms demonstrate that the system provides a {sup 238}U rejection factor of >10{sup 7}. Recently, we have utilized the high dynamic range of the AMS system in measuring samples whose Pu contents ranged from <10{sup 6} (background) to >10{sup 11} Pu atoms. Measurements of known materials, combined with results from an externally organized intercomparison program, indicate that our {sup 239}Pu measurements are accurate and precise down to the {mu}Bq level ({approx}10{sup 6} atoms). …

In order to enable continuous operation of a Laser Inertial confinement Fusion Energy (LIFE) engine, the material (fill-gas and debris) in the fusion chamber must be carefully managed. The chamber chemical equilibrium compositions for post-shot mixtures are evaluated to determine what compounds will be formed at temperatures 300-5000K. It is desired to know if carbon and or lead will deposit on the walls of the chamber, and if so: at what temperature, and what elements can be added to prevent this from happening. The simulation was conducted using the chemical equilibrium solver Cantera with a Matlab front-end. Solutions were obtained by running equilibrations at constant temperature and constant specific volume over the specified range of temperatures. It was found that if nothing is done, carbon will deposit on the walls once it cools to below 2138K, and lead below 838K. Three solutions to capture the carbon were found: adding pure oxygen, hydrogen/nitrogen combo, and adding pure nitrogen. The best of these was the addition of oxygen which would readily form CO at around 4000K. To determine the temperature at which carbon would deposit on the walls, temperature solutions to evaporation rate equations needed to be found. To determine how much …

The Cancer Genome Atlas Network recently cataloged recurrent genomic abnormalities in glioblastoma multiforme (GBM). We describe a robust gene expression-based molecular classification of GBM into Proneural, Neural, Classical, and Mesenchymal subtypes and integrate multidimensional genomic data to establish patterns of somatic mutations and DNA copy number. Aberrations and gene expression of EGFR, NF1, and PDGFRA/IDH1 each define the Classical, Mesenchymal, and Proneural subtypes, respectively. Gene signatures of normal brain cell types show a strong relationship between subtypes and different neural lineages. Additionally, response to aggressive therapy differs by subtype, with the greatest benefit in the Classical subtype and no benefit in the Proneural subtype. We provide a framework that unifies transcriptomic and genomic dimensions for GBM molecular stratification with important implications for future studies.

Neutralization and focusing of intense charged particle beam pulses by a background plasma forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal …